Separable catheter insertion device

ABSTRACT

A disposable catheter insertion device has a longitudinal slot running the length of the needle and of the hub member secured to the needle. The slot facilitates removal of the catheter from the needle after insertion of the catheter into a patient. A clip member slidably coacts with the hub member and a coupling sleeve to prevent longitudinal movement of the catheter during insertion into a patient.

United States Patent 1 151 3,682,173 Center [451 Aug. 8, 1972 SEPARABLE CATHETER INSERTION 3,297,030 1/ 1967 Czorny et a1. ,.128/214.4 DEVICE 3,330,278 7/1967 Santomieri 128/214.4 [72] Inventor: John L. Center DanasTex 7 2,707,953 5/1955 Ryan ..128/214 R 73 Assignee: Vicra Sterile, Inc., Dallas, Terr. FOREIGN PATENTS OR'APPLICATIONS [22] Fil d; 1 1970 904,237 8/1962 Great Britain ..128/214.4

21 Appl. No.: 81,458 Primary Examiner-Dalton L. Truluck AttorneyRichards, Harris & Hubbard [52] US. Cl. ..-...l28/214.4, 128/D1G. 16, 128/221,

128/348 [57] ABSTRACT v [51] Int. Cl. ..A6lm 05/00 A'dis posable catheter insertion device has a longitu- [58] new of Search 2 bi dinal slot running the length of the needle and of the I hub member secured to the needle. The slot facilitates 56] R f Cted removal of the catheter from the needle after insertion e erences I of the catheter into a patient. A clip member slidably UNITED STATES PATENTS coacts with the hub member and a coupling sleeve to prevent longitudinal movement of the catheter during 3,561,445 2/1971 Katemdahl et a1. ....128/214.4 insertion into a patient 3,472,232 10/1969 Earl ..128/348 3,545,443 12/ 1970 Ansari ..128/214.4 13 Claims, 14 Drawing Figures Patented Aug. 8; 1972 3,682,173

2 Sheets-Sheet 2 .1 SEPARABLE CATHETER INSERTION DEVICE BACKGROUND OF THE INVENTION This invention relates to medical devices for subcutaneous introduction of fluids into a patient, and more specifically to a catheter and insertion device therefor. These devices are generally used for intravenous infusion, however, they also can be used for infusion or withdrawal of fluids into or from other regions of the body. Hereafter, for purposes of simplicity, the devices will be referred to in relation to intravenous infusion.

Catheters of the general type disclosed herein are available commercially and have been disclosed in the prior art. For example, self-contained catheters and insertion devices therefor are disclosed in U.S. Pat. Nos. 3,000,380; 3,010,453; 3,017,884, and 3,055,361. This general type of catheter was developed for usage where administration of fluids to a patient had to be either continuous or where such administration was intermit tent over a prolonged period.

Prior to the development of the self-contained catheters and insertion devices, intravenous or other infusion of fluid into a patient was accomplished by means of a sterile needle. This needle was utilized to puncture the skin and vein of a patient. The needle was then taped to the surface of the skin. A conduit coupled to a source of intravenous fluid, for example, a syringe or gravity bottle type infusion fluid source, was then connected to the needle. Generally, this type of device has been unsatisfactory. Due to the rigidity of the needle and muscle flexure of the patient, it was necessary to remove the needle when an infusion was finished, and to reinsert the needle each time a new infusion was to be given. The repetitive removal and reinsertion of the needle caused puncture damage and bruising to the area of the patient into which the needle was being inserted. Therefore, those in the medical field have come to prefer the flexible catheter infusion method. The prior art flexible catheters for infusion of fluids into the veins of patients generally include a hollow needle and a fairly long flexible hollow cannula, the catheter. One end of the catheter usually has'a coupling means or mechanism thereon, for example of the: luer type, for connection to a source of infusion liquid. The other end of the catheter is slidably disposed within the bore of the hollow needle. The hollow needle is then inserted into a vein of a patient. The catheter is pushed through the hollow portion of the needle into the vein. The needle is then removed leaving the catheter protruding from the body of the patient. One of the advantages of this type of injection apparatus is that the needle, catheter and coupling means can be completely enclosed in a sterile package which is unopened until the time it is to be used with a patient. In addition,-the materials utilized can be sufficiently economic to render such devices disposable after use. Thus, the chances of contamination or the spreading of infection is substantially lessened compared to the reusable type injection devices which must be resterilized after every 4 of larger diameter than the needle bore, as above explained. Since the needle cannot be removed, it is continuously present on the catheter outside the patients body. In the past, the presence of the needle has been troublesome due to its bulkiness and to the fact that the patients skin can easily be accidentally punctured by the needle point.

- Damage to the catheter from the needle can also result. But more importantly, a catheter must sometimes be partially withdrawn during the insertion process resulting in accidental cutting or severing of the catheter by the needle point within the patients body. Not only can the severed end of the catheter thus lodge within the patient, ,but also small chips or shavings from the catheter wall can remain within the patients body. These results are, of course, intolerable. Various means have been proposed for resolving these problems. The initial method proposed was merely to tape the needle with the catheter running through it to the patients arm thereby keeping it out of the way. However, the danger of damage to the catheter and to the patients skin still was present although not in as great a'proportion. Another solution is disclosed in U.S. Pat. No. 3,055,361. In that patent, a sleeve which is slidably inserted around the needle prior to its insertion into the patients arm is disclosed. The sleeve is positioned on the portion of the needle which remains exterior to the patients body. After the catheter has been inserted and the needle withdrawn from the patient, the sleeve is moved toward the pointed end of the needle to cover it. Frictional contact between the portion of the sleeve not extending beyond the pointed end of the needle retains the sleeve on the needle. Thus, the

pointed end of the needle is covered preventing damage to the patient. This apparatus, however, still has drawbacks. The possibility of damage to the catheter itself still exists since it is not protected from the pointed end of the needle by the sleeve. In addition, the bulky needle is still present and still must be taped or tied to the patients arm.

' Still another approach to the problem, representing an advance over the prior attempts, is disclosed in U.S. Pat. No. 3,472,232. This patent discloses a hollow needle containing a longitudinal slot running along its entire length. The needle, of course, is pointed at one end. A pressure member isv connected to the other end which serves as a needle hub. Hinged to the pressure member or needle hub is a projection which can be moved in and out of a slot in the pressure member and through the needle slot to contact a catheter slidably disposed in the needle. After the catheter is inserted into a patient, the needle can be withdrawn from the patients body and separated from the catheter by pulling upwardly on the projection to remove it from the slot in the pressure member and pulling the catheter through the slot in the needle and the pressure member. Although representing an advance over' prior attempts at dealing with the needle after removal from the patients body, this concept still retains significant disadvantages. For example, in order to operate the catheter insertion device of the aforementioned patent, two hands are necessary; one to hold the needle and the other to release the pressure member so that the catheter can be inserted. Usually it is desirable for a sole operator of such a catheter insertion device to appendage while holding onto the needle insertion device with the other hand. In addition, the device disclosed in the above-mentioned patent makes no provision for maintaining the catheter in a sterile environment during insertion. This also is important in that the atmosphere surrounding the patient during insertion of the catheter may not be sufficiently sterile to prevent the spread of infection into the puncture wound made by the catheter insertion needle. In addition, the pressure member of the device disclosed in the above-mentioned patent must also be held down with one finger of the hand inserting the catheter insertion needle into a patient in order to seize thecatheter. It is important that the pressure member seize or contact the catheter I to prevent the catheter from sliding longitudinally backwardly in the needle while it is being inserted. It is most desirable to maintain the forward end of the catheter near the pointed tip of the insertion needle while the two are being initially inserted into a patients .body

It is, therefore, found desirable to develop a catheter insertion device in which the needle can be completely separated from the catheter containing a coupling mechanism at its distal end. In addition, it is. desirable to possess ,a catheter insertion device which allows manipulation'and insertion ofthe needle and catheter into a patient with only one hand of the operator. In ad SUMMARY OF INVENTION The present invention, therefore, solves the foregoing problems while incorporating .the' desirable attributes of a disposable catheter insertion device. The subcutaneous catheter insertion device of the presentinvention comprises. a needle having a longitudinal bore therethrough, one end of said needle adapted to facilitate puncture of and insertion into subcutaneous tissue, said needle having a longitudinal slot extending the length thereof, a hub member secured to the distal end of the needle having a longitudinal slot therein, a flexible catheter having one end slidably disposed in the bore of the needle and extending rearwardly therefrom, a coupling member connected operatively to the hub member, and means associated with the coupling member and movable to coact with a portion of Y the catheter between a first position and a second position, the means in the first position preventing longitudinal movement of the catheter in the needle. In an alternative embodiment of the subcutaneous catheter insertion device, the means can be removably associated with the hub member and longitudinally movable between a first and a second position, the means in the first position preventing longitudinal movement of the catheter in the needle.

of the present invention; 1

catheter from the slot thereof;

4 BRIEF DESCRIPTION OF DRAWINGS conjunction with the accompanying drawings, in

which:

FIG. 1 is a partially exploded perspective view of the catheter and insertion device of the present invention;

FIG. 2 is a side perspective view'of' the present invention showing it completely assembled and partially enclosed by an internally sterile plastic bag;

FIG. 3 is a partial longitudinal cross-sectional view of the catheter and insertion device of the present invention;

FIG. 4 is a full cross-sectional view of the device taken along a section similar to that of 4'4 of FIG. 3;

FIG. 5 is an enlarged top view of theinsertion needle FIGS. 6, 7, and 8 are respectively top, front and side views of the stop button of the present invention; 7

FIG. 9 is a schematic illustration of the method of insertion of the catheter of the present invention into a patients vein;

FIG. 10 is a partial cross-sectional view of the insertion device and coupling member of the present invention showing the release position for the stop button;

FIG. 11 is a perspective view of the needle insertion device of the present invention showing removal of the FIG. 12 is a schematic view of the catheter after the needle has been removed therefrom;

FIG. 13 is a top view of an alternate embodiment of the insertion needle of the present invention;

FIG. 14 is a cross-sectional view of the alternate embodiment of FIG. 13 taken along section line l414.

DESCRIPTION OF PREFERRED EMBODIMENTS As heretofore explained, thepresent invention will be described in relation to an intravenous catheter insertion device. It is to be understood that other subcutaneous punctures can be effected with the present invention for insertion of the catheter disclosed herein into other portions or regions of the body of the patient. Therefore, the invention is intended to be limited only by the definition contained within the appended claims.

Referring now to FIG. 1, a view of a partially disassembled catheter and insertion needle of the present invention is illustrated. Hollow needle 10, preferably made of a surgical steel, has one end which is cut at a taper to form a point 12. The otherend of the needle is secured in a hub member 14. Both needle 10 and hub member 14 contain longitudinal slots (better seen in later figures). A coupling sleeve 16 is arrangedfor sliding and removable attachment to a rearward projection 18 on the hub member 14. A clip member 20 is positioned in a channel formed when the-coupling sleeve 16 is slidably disposed upon the rearward projection 18. The hub member'l4 is also provided with a circular portion 22 of reduced diameter onto which a needlepolytetrafluoroethylene, or other suitable material. The

catheter extends through the hub member 14 and along a trough (better seen in later figures) contained in the rearward projection 18. It extends through the coupling sleeve 16 and terminates at its distal end in a suitable fitting 28, for example a luer female fitting. A luer plug 30 is provided for sealingly closing the open end of the fitting 28. The plug 30 is provided to prevent egress of body fluids from the catheter when it is being inserted and also when the catheter is not attached to a fluid infusion device.

In FIG. 2, the needle cover 24 is shown secured 'onto the reduced diameter portion 22 of the hub member 14. In addition, plug 30 is disposed in the luer fitting 28. The coupling sleeve 16 has sealed around its distal cir cumference a flexible, preferably transparent sac 32 sealed at its distal end 34. One function of the coupling sleeve 16 is to maintain the sac 32 around the catheter 26, the luer fitting 28 and plug 30 to provide a sterile environment. Primarily, the coupling sleeve 16 serves to retain the clip member 20 in contact with the catheter 26, as will be better seen later.

The hub member 14, including its rearward projection 18, needle cover 24, coupling sleeve 16, and clip member 20 are preferably molded from synthetic polymeric materials such as polyethylene, polytetrafluoroethylene, polyamides, or some other material which is capable of being molded. The flexible sac 32, manufactured from, for example polyurethane, polyethylene or polyester film, can be attached to the coupling sleeve 16 by heat sealing or can be merely taped about the sleeve member utilizing a thin strip of adhesively backed tape.

Normally, the interior and exterior of the needle 10, the interior of cover 24, the catheter 26, luer fitting 28, and plug 30 as well as the entire interior of the flexible sac 32 are sterilized during manufacture of the catheter device. Of course, the interior of the coupling sleeve 16 is also sterilized as well as the interior portion of the clip member 20. After the catheter device as shown in FIG. 2 is completely assembled, it is housed in a package (now shown) in which the sterilization procedure takes place. The package and contents are usually rendered sterile by the introduction of a gas, such as ethylene oxide, into the package. The device can also be easily transported and handled in the package without danger of contamination prior to use.

Referring now to the cross-sectional views of FIG. 3 and FIG. 4, the needle has formed therein a longitudinal slot 54. The needle cover 24 is secured upon the reduced diameter portion 22 of the hub 14. The clip member is slidably disposed in a channel 40 formed by the rearward projection 18 of the hub member 14 and coupling sleeve 16. The clip 20 is composed of a bottom portion 42 of sufi'rcient vertical height so as to intimately contact the upper interior wall of the coupling sleeve 16 and also to press the catheter 26 against the upper interior surface of the rearward projection 18 of the hub member 14. This coaction of the lower portion 42 of the clip member 20 operates to prevent longitudinal movement of the catheter 26 as it is introduced into a patient. A second portion 44 of the clip member 20 extends upwardly through a longitudinal slot 46 in the coupling sleeve 16. The portion 44 of the clip 20 terminates above the coupling sleeve 16 in a finger or thumb grip 48 containing serrations or ridges on the top thereof. During insertion of the needle and catheter into a patient, the clip member rides in the position shown in FIG. 3.

FIG. 4 is a full transverse cross-sectional view taken along a line similar to line 4-4 of FIG. 3, which better illustrates the operation of the clip 20 in relation to the catheter 26. The rearward projection 18 of the needle hub 14 contains a trough or channel 50 generally of semi-circular cross section extending the full length of the projection 18. The catheter 26 rides therein. The upper surface of the bottom portion 42 of clip 20 contacts the upper interior wall of coupling sleeve 16. As it does so, it is forced down upon the top surface of the catheter 26 so as to deform the catheter, thus frictionally engaging the catheter between the bottom surface of the bottom portion 42 of the clip member 20 and the walls of the channel 50 in the projection 18. The frictional engagement between the channel 50 and the bottom portion 42 prevents longitudinal movement of the catheter 26 as it is inserted into a patient.

The construction of the hub member 14 and the re arward projection 18 integrally a part thereof as well as the channel is better understood by reference to FIG. 5. There the needle is shown secured in the hub member 14, preferably integrally molded therewith. The longitudinal slot 52 in the hub member 14 and the longitudinal slot 54in the needle 10 are provided so that after the catheter has been inserted into a patient and the needle removed leaving the catheter in the patient, the catheter can be separated from the needle and hub member as shown in conjunction with FIG. 1 l.

Optionally, a wire stylet 58 as illustrated in FIG. 3 can be attached to the luer plug 30. The stylet extends from the plug 30 to ordinarily within a half inch from the end of the catheter as shown. The stylet lends rigidity to the catheter for easier insertion into a patient. It should be noted that the interior opening through the coupling sleeve 16 is of sufiicient diarnetral size such that the luer fitting 28 and plug 30 can pass through the sleeve 16 so that the sleeve and sac 32 can be completely removed from the assembly. In addition, it

should be noted that the upwardly extending walls 60 shown both in FIGS. 3 and 5 are provided so that the coupling sleeve 16 will have additional surface area on the rearward projection to contact so that it will be held sufficiently tight merely by frictional contact. The distance between the interior sides of the upwardly extending walls 60 must be sufficiently wide to allow free passage of the bottom portion 42 of the clip member 20 therebetween.

' FIGS. 6, 7, and 8 present top, front and side views, respectively, of the clip member 20. It is seen that the clip member is generally T-shaped and includes a lower portion 42 which is slidably disposed in the channel formed by the coupling sleeve and the rearward projection on the hub member. The middle portion 44 extends upwardly through the slot 52 in the coupling sleeve and terminates in the thumb grip 48. Thumb grip 48 has the ridges 56 for increasing a frictional grip between the thumb and the clip member.

With respect to operation of the catheter device, refer to FIGS; 9 through 12. The needle cover 24 is first The catheter 26 is thus released from the grasp of the lower portion 42 of the clip member so that is is freely and slidably disposed within the coupling sleeve, hub

memberand needle-As can be seen in FIG. 10, the

raised portion 72 atthe'front end of the coupling sleeve 16 contacts the lower surface of the thumb grip 48 such serted the desired distance into a patients vein, the

needle is removed from the patients-body leaving the catheter in place in the vein. Thereafter, the coupling sleeve 16 is removed from the rearward projection 18 of the. hub member 14. It is also removed completely over the luer fitting and plug attached to the distal end of the catheter. The coupling member, sac and clip member 20 then can be discarded.

Thereafter, the catheter can be separated from the needle and hub member by' pulling the catheter through the slot 54 in the needle 10 and through the slot 52 in the hub member 14 as shown in FIG. 11; The

luer fitting 28 can be attached to an infusion source such as the intravenous bottle 74 shown in FIG. 12 at any time after the sac is removed. It is, of course, to be understood that the catheter is made from a sufficiently flexible material to allow radial deformation thereof as his removed through the slot 54. Such materials include polyurethane and polytetrafluoroethylene as mentioned above. The slot 54 in the needle is preferably of a slightlysmaller width than the diameter of the catheter 26' so that it must necessarily be deformed in order to be removed. This size relationship of the catheter and slot is important since it will cause the catheter to be retained inthe needle at all times untilit is forceably removed. The width of the slot 52 in the hub member. 14 is generally of slightly greater width than the catheter 26 so that removal therefrom can be accomplished with ease.

1 An alternative embodiment of the present invention isshown in FIGS. 13 and 14. In this embodiment, the hub member, rearward projection and coupling sleeve are combined into one assembly, generally designated 80. Referring to both FIGS. Band 14, a needle 82 is integrally molded into the assembly 00. The needle is provided with a slot like that of needle 10 referred to above in conjunction with the preferred embodiment.

The assembly 80 contains a longitudinal slot 83 correspondent with the needle slot along its entire length.

tionally engages the catheter 96 between the bottom portion of the clip member and the bottom of the channel 90 thus holding the catheter longitudinally stable. during insertion. After the needle and catheter have been inserted into a patients body, the clip member 92 is moved forward in the direction of arrow- 98 and removed through opening 94. Thus the catheter 96 is freed so that it is slidably disposed in the assembly 80 A forward wall 84, a rear wall 86 and the top portion 88 of the assembly form an interior channel 90 in which is slidably mounted a clip member 92 similar. to that I therethrough. During insertion of the catheter, the clip member 92 is in a rearward position so that it fricand needle 82, allowing manipulation of the catheter into a patients body. Once the needle has been removed from the patient leaving the catheter inserted, the catheter can be separated from the needle and clip member through the needle slot and the slot 8 3 in the needle assembly 80.

As one of j ordinary skill in the art to which the devices of the subject invention pertain is aware, many variations and alternatives of thepresent device can be provided without departing from the basic invention. The invention, therefore, is to be limited only as defined in the appended claims.

What is claimed is: t

1. A subcutaneous catheter insertion device comprisa needle having a longitudinal bore therethrough,

having a longitudinal slot therein aligned with said needle slot;

a walled casing having a hollow interior extending rearwardly of said hub, and an aperture means through said casing walls;

catheter bearing plate means positioned casing opposite said aperture means;

a flexible catheter having one end slidably disposed in said bore of said needle and extending rearwardly through the hub and the said hollow interior of said casing over said'catheter bearing plate means and terminating ina distal end rearwardly of said casing; A

releasable catheter holding means having a part carriedintemally of said hollow interior of said casing and an actuating means extending externally therefrom through said aperture means;

said holding means being movable by manipulation of said actuating means to move the said part car-' ried internally from a normal locked position in the said hollow interior to an unlocked position in said hollow interior; and

said catheter located on said catheter-bearing plate means being frictionally engaged by said part carried internally when in the normal locked position and being released to permit longitudinal movewithin said ment when the said part can'ied internally is ture of and insertion into subcutaneous tissue, said needle having a longitudinal slot extending the length thereof;

a hub member secured to the distal end of the needle having a longitudinal slot therein aligned with said needle slot;

a walled casing having a hollow interior extending rearwardly of said hub, said casing having an enlargement only in a portion of said hollow interior, said casing further having aperture meansthrough said casing walls; I

catheter bearing plate means positioned within said casing opposite said aperture means;

a flexible catheter having one end slidably disposed in said bore of said needle and extending rearwardly through the hub and the said hollow interior of said casing and over said catheter bearing plate means and terminating in a' distal end rearwardly from said casing; releasable catheter holding means having a part carried internally of said hollow interior of said casing and a part extending externally therefrom through said aperture means; said holding means being movable by manipulation of said part extending externally to move the said part carried internally from a normal position in Y the said hollow interior to the enlargement in said hollow interior;

said catheter located on said catheter bearing plate means being frictionally engaged by said part carried internally when in the normal position and being released to permit longitudinal movement thereof when the said part carried internally is moved into the enlargement in said hollow interi- 4. The device of claim 2 wherein said casing is a coupling removably engaged with said hub member.

5. The device of claim 4 further comprising an integral rearward projection from said hub member.

6. The device of claim 5 wherein said enlargement is provided by an increased diarnetrical portion of said casing; and

the said normal position is rearward of said enlargement in said hollow interior.

7. The device of claim 6 further comprising a pliable elongated sac attached to said coupling member and surrounding and fully enclosing the said distal end.

8. A subcutaneous catheter insertion device comprismg:

. a needle having a longitudinal bore therethrough,

one end of said needle adapted to facilitate puncture of and insertion into subcutaneous tissue, said needle having a longitudinal slot extending the length thereof;

a hub member secured to the distal end of the needle having a longitudinal slot therein, said hub member having a projection extending rearwardly therefrom with a longitudinal slot in register with the slot in said hub member;

a flexible catheter having one end slidably disposed in said bore of said needle and extending rearwardly therefrom through the said longitudinal slot in said hub and the said longitudinal slot in said a 32ft? easing having a hollow interior, said casing overlying said projection with said hollow interior in communication with said slot in said projection; said casing having an enlarged diarnetrical portion and aperture means through said walls;

a frictional lug riding in the hollow interior of said casing just over the'slot in said projection, said lug having a finger button extending externally from said casing through said aperture;

said lug being movable by manipulation ofsaid finger button from a position in frictional contact with a catheter disposed in said longitudinal slot in said projection to a position in the enlarged diarnetrical portion of said casing where said lug is out of frictional engagement of said catheter.

9. The device of claim 8 wherein said casing is a removable coupling carried over said hub projection into engagement with said hub member.

10. The device of claim 8 wherein said casing and said hub are integral, said casing having a channel extending its full length to permit a catheter to be completely removed from said casing.

11. The device of claim 10 further comprising an enlargement in a portion only of the said channel to permit the said lug to be removed from said casing.

12. The device of claim 8 wherein said increased diarnetrical portion is provided by enlarged external dimensions of portions of said walled casing which have a uniform wall thickness.

13. The device of claim 8 wherein said increased diarnetrical portion is provided by enlargedinternal dimensions of said casing with the external dimensions of said casing being substantially uniform.

292 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CQRRECTIQN Patent No. 2, 682.172 Dated August 8, 1972 I mfl John L. Center It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 3, lineal, "in the" shoald re d -j.n a--.

C01. 5, line 16, "how" should read --not-.

Col. 7 line 8, "is is" should read -it is-.

Col 8, Claim 2, "Claim 2", should read --C'laim 3--.

Col. 9, Claim "Claim 2" should read ---c1 aim'3-=-.

Signed and sealed this 23rd day of January 1973.

(SE L 'Attest:

EDWARD M.FLETCHER,JR. I ROBERT GOTTSCHALK Attescing Officer Commissioner of Patents 

1. A subcutaneous catheter insertion device comprising: a needle having a longitudinal bore therethrough, one end of said needle adapted to facilitate puncture and insertion into subcutaneous tissue, said needle having a longitudinal slot extending the length thereof; a hub member secured to the distal end of the needle having a longitudinal slot therein aligned with said needle slot; a walled casing having a hollow interior extending rearwardly of said hub, and an aperture means through said casing walls; catheter bearing plate means positioned within said casing opposite said aperture means; a flexible catheter having one end slidably disposed in said bore of said needle and extending rearwardly through the hub and the said hollow interior of said casing over said catheter bearing plate means and terminating in a distal end rearwardly of said casing; releasable catheter holding means having a part carried internally of said hollow interior of said casing and an actuating means extending externally therefrom through said aperture means; said holding means being movable by manipulation of said actuating means to move the said part carried internally from a normal locked position in the said hollow interior to an unlocked position in said hollow interior; and said catheter located on said catheter-bearing plate means being frictionally engaged by said part carried internally when in the normal locked position and being released to permit longitudinal movement when the said part carried internally is moved into the unlocked position in said hollow interior.
 2. The device of claim 2 wherein said enlargement is provided by an increased diametrical portion of said casing.
 3. A subcutaneous catheter insertion device comprising: a needle having a longitudinal bore therethrough, one end of said needle adapted to facilitate puncture of and insertion into subcutaneous tissue, said needle having a longitudinal slot extending the length thereof; a hub member secured to the distal end of the needle having a longitudinal slot therein aligned with said needle slot; a walled casing having a hollow interior extending rearwardly of said hub, said casing having an enlargement only in a portion of said hollow interior, said casing further having aperture means through said casing walls; catheter bearing plate means positioned within said casing opposite said aperture means; a flexible catheter having one end slidably disposed in said bore of said needle and extending rearwardly through the hub and the said hollow interior of said casing and over said catheter bearing plate means and terminating in a distal end rearwardly from said casing; releasable catheter holding means having a part carried internally of said hollow interior of said casing and a part extending externally therefrom through said aperture means; said holding means being movable by manipulation of said part extending externally to move the said part carried internally from a normal position in the said hollow interior to the enlargement in said hollow interior; said catheter located on said catheter bearing plate means being frictionally engaged by said part carried internally when in the normal position and being released to permit longitudinal movement thereof when the said part carried internally is moved into the enlargement in said hollow interior.
 4. The device of claim 2 wherein said casing is a coupling removably engaged with said hub member.
 5. The device of claim 4 further comprising an integral rearward projection from said hub member.
 6. The device of claim 5 wherein said enlargement is provided by an increased diametrical portion of said casing; and the said normal position is rearward of said enlargement in said hollow interior.
 7. The device of claim 6 further comprising a pliable elongated sac attached to said coupling member and surrounding and fully enclosing the said distal end.
 8. A subcutaneous catheter insertion device comprising: a needle having a longitudinal bore therethrough, one end of said needle adapted to facilitate puncture of and insertion into subcutaneous tissue, said needle having a longitudinal slot extending the length thereof; a hub member secured to the distal end of the needle having a longitudinal slot therein, said hub member having a projection extending rearwardly therefrom with a longitudinal slot in register with the slot in said hub member; a flexible catheter having one end slidably disposed in said bore of said needle and extending rearwardly therefrom through the said longitudinal slot in said hub and the said longitudinal slot in said projection; a walled casing having a hollow interior, said casing overlying said projection with said hollow interior in communication with said slot in said projection; said casing having an enlarged diametrical portion and aperture means through said walls; a frictional lug riding in the hollow interior of said casing just over the slot in said projection, said lug having a finger button extending externally from said casing through said aperture; said lug being movable by manipulation of said finger button from a position in frictional contact with a catheter disposed in said longitudinal slot in said projection to a position in the enlarged diametrical portion of said casing where said lug is out of frictional engagement of said catheter.
 9. The device of claim 8 wherein said casing is a removable coupling carried over said hub projection into engagement with said hub member.
 10. The device of claim 8 wherein said casing and said hub are integral, said casing having a channel extending its full length to permit a catheter to be completely removed from said casing.
 11. The device of claim 10 further comprising an enlargement in a portion only of the said channel to permit the said lug to be removed from said casing.
 12. The device of claim 8 wherein sAid increased diametrical portion is provided by enlarged external dimensions of portions of said walled casing which have a uniform wall thickness.
 13. The device of claim 8 wherein said increased diametrical portion is provided by enlarged internal dimensions of said casing with the external dimensions of said casing being substantially uniform. 